Eric Holder, the US attorney general, launched an attack Tuesday on self-defence laws he said encouraged more violence, and used George Zimmerman's acquittal over the murder of Trayvon Martin as a backdrop to call for a deeper debate about issues of race and gun controls.

Addressing the annual convention of the National Association for the Advancement of Colored People in Orlando, Florida, close to the town of Sanford where Martin was killed in February last year, Holder insisted it was time to look again at legislation such as the state's stand-your-ground law that eliminated "the commonsense and age-old requirement" that people who felt threatened had a duty to retreat.

"These laws try to fix something that was never broken," he said. "We must stand our ground to ensure that our laws reduce violence and take a hard look at laws that contribute to more violence than they prevent.

"By allowing and perhaps encouraging violent situations to escalate in public, such laws undermine public safety. The list of resulting tragedies is long and unfortunately has victimised too many who are innocent."

The speech by Holder, the country's first African American attorney general, was warmly received by members of the NAACP, who have been vocal since Zimmerman's controversial murder acquittal on Saturday in their demands for the neighbourhood watch leader to face a federal civil rights prosecution.

Holder repeated his promise that Martin's "tragic and unnecessary" death would be fully investigated by the Department of Justice as it determined whether legal action could be taken.

"The NAACP and its members are deeply and rightly concerned about this case, as passionate civil rights leaders, engaged citizens and most of all as parents," he said.

"The Department of Justice will consider all available information before determining what action to take. But independent of the legal determination, I believe this tragedy provides yet another opportunity for our nation to speak honestly and openly about the complicated and emotionally-charged issues that this case has raised."

Recalling stories from his own childhood, he spoke of the progress that still needed to be made in race relations in the US.

"Years ago, some of these same issues drove my father to sit down with me, to have a conversation about how, as a young black man, I should interact with the police, what to say and how to conduct myself, if I was ever stopped or confronted in a way I thought was unwarranted," he said.

"I'm sure my father felt certain at that time that my parents' generation would be the last to have to worry about such things for their children. Since those days our country has indeed changed for the better.

"Yet for all the progress we have seen, recent events demonstrate that we still have much more work to do and much further to go. The news of Trayvon Martin's death last year and the discussions that have taken place since then reminded me of my father's words."

Holder said he had spoken with his own 15-year-old son, "not to burden him with the baggage of eras long gone, but to make him aware of the world he must still confront."

"This is a sad reality in a nation changing for the better in so many ways," Holder added. "I am determined to ensure that the kind of talk I had with my son isn't the only conversation we engage in as a result of these tragic events."

He addressed the protests that followed Zimmerman's acquittal, which, apart from a small number of arrests in California, were largely peaceful. "In the days leading up to the weekend's verdict, some predicted and prepared for riots and waves of civil unrest across the country. Some feared that the anger of those who disagreed with the jury might overshadow and obscure the issues," he said.

"The people of Sanford and for most part thousands of others across America, rejected this destructive path. They proved wrong those who doubted their commitment to the rule of law and across America diverse groups of citizens are instead overwhelmingly making their voices heard through rallies and vigils designed to provoke responsible debate.

"Those who act in a contrary manner do not honour the memory of Trayvon Martin," Holder said. © Guardian News and Media 2013